Spectral cues utilized in monaural localization will be investigated. Under monaural listening conditions, narrow bands of noise centered at frequencies from 4.0 through 14.0 kHz possess apparent locations which are governed by these center frequencies. One aim of this research will be to find out how these spatial referents of stimulus frequency enters into the process of monaural localization. This will be carried out through selective filtering of the sound spectrum during a monaural localization task. A second aim of the study is to measure the effects of a variety of initial exposures to a sound localization task on subsequent localization performances. The experimental design draws upon one of the transfer of training paradigms. What is unique in these proposed experiments is that the test will consist of only one trial per session and extend over many sessions. In this way, the testing procedure per se will not obliterate, or strongly attenuate, the effect of the pre-test experience.